DE3233924C2 - Endoscope with a solid-state imaging device - Google Patents

Abstract

An endoscope has a body (1) which is provided with an imaging optical system (12), a self-scanning solid-state image pickup device (13) on which cyan and yellow color filters are alternately arranged in correspondence with the respective picture elements of the image pickup device, and a light guide (14). When green light is emitted from the light guide, image signals corresponding to the green component of the object are picked up from all the picture elements. When white light is emitted, cyan component image signals are picked up by the picture elements on which the cyan filters are arranged and yellow component signals are picked up by those on which the yellow filters are arranged. Alternatively, when green light is emitted, green component signals are picked up from all of the picture elements, and when gastric light is emitted, blue component signals are taken from the picture elements on which the cyan filters are arranged and red component signals from those on which the yellow filters are arranged are included. The image signals are then electrically processed to produce a color image.

Description

The invention relates to an endoscope for observing and recording the interior of a body cavity or a machine with an imaging optical system that creates an image of an object, with one that is used by the optical imaging system

system to convert the generated image into an electrical signal self-scanning solid-state image recording device and with a lighting device illuminating the object, wherein the imaging optical system, the solid-state image pickup device, and the lighting device are mounted one in a body cavity or the interior of a machine-insertable endoscopic body are arranged, as is disclosed in US Pat 40 74 306 is known.

In general, endoscopes are also used as fiber viewing devices can be used to refer to the interior of body cavities or objects to look at and record pictures of the interior. An end section of the in the to be viewed Inner inserted endoscope is at least equipped with an imaging optical system for training of an image of an object, and one end of an optical fiber bundle that acts as an image guide optical image produced by the imaging system to its other end is in this one End section contains as well as one end of an optical fiber bundle that acts as a light guide for crie lighting the object serves. The optical image transmitted by the image guide is then enlarged through a magnifying glass, to facilitate observation, and recorded on photographic film or by a Cathode ray tube made visible.

Advances in semiconductor technology in recent years Times have led to widespread use of solid-state self-scanning image pick-up devices, such as for example charge coupled devices (CCD's). and television cameras, which are solid-state imaging devices use of this type have come into practical use. The solid-state imaging devices of this type have compared to the image pickup tubes commonly used in television cameras, like vidicons. an advantage in that they are smaller in size and lighter in weight. Based on this wi "-de in Japanese Patent Laid-Open 51 (197b) 65,962 and 49 (1975) 114,940 and U.S. Patent 4,074,306 Solid-state self-scanning image pick-up device directly into the above-mentioned end portion of an endoscope and that of the optical imaging system Convert the produced image of an object into an electrical signal in order to display a television image to represent an image receiver (cathode ray tube vision device).

Lim a Farbfcmse ^h to obtain image on a Kathodensirahlrohrensichtgerät, generally one of the Biidaufnahmesysteme described below is applied. In the first and basic system, the image of an object produced by an imaging optical system is separated into colors into red, green and blue color images, and there are three separate solid-state image pickup devices. which correspond to the three basic colors are used. In the second system, only a solid-state imaging device is used, and red. Green and blue primary color filters are arranged in a mosaic form for respective picture elements of the solid-state image pickup device in order to achieve a multiple utilization of the image pickup area. In the third system (US-PS 40 74 306) RoI-. Green and blue primary color filters are guided past a light source at a specified speed and emit light to the exposing part of the endoscope, i.e. to the above-mentioned fiber bundle called light guide, and the red, green and blue primary color components of the image are in recorded in a plan-sequential manner by a single, kest image recording device. However, these conventional systems pose very significant problems when used for endoscopes. The first system cannot be integrated into a small and narrow end section of an endoscope, although it offers the best basic equipment and design and gives off good television images. if

ίο the first system in the end section of an endoscope is inserted, where this end portion becomes voluminous and the scope of the endoscope is limited. The second system can be built into a small end section of an endoscope. However, since in this system, the image pickup surface of the solid-state image pickup device is separated in color by red, green and blue primary color filters in mosaic form, the number of picture elements for the green component, which determines the resolution, is changes what leads to a humiliation ..- ·, resolving power leads. When the end portion of the endoscope is small, it is particularly difficult to use a solid-state image pickup device to use which has many picture elements poses a lowering in resolving power in this case therefore represents a very serious problem in the third system, the three primary color components of the image in succession from a single one Solid-state imaging device in a plan-sequential manner, d. H. consequently on one level, It is necessary to sequentially capture an object with red, green and blue primary color lights to illuminate. Therefore brings the to align or coincide with the three primary color images necessary time problems in terms of quality deterioration when the object is moving at a relatively high speed.

The invention is based on the object of developing an endoscope of the type mentioned at the outset in such a way that that the endoscope body to be inserted into the interior of a body cavity or machine is small in size can be obtained, a good resolving power is guaranteed, recording errors eliminated and the time for recording de, color signals is reduced.

In the case of a generic endoscope, this object is achieved by the characterizing part of the claims 1 or 7 described measures solved.

Preferred developments and configurations of the endoscope according to the invention are the subject matter of claims 2 to 6 or 8 to 12.

In the image pickup device of the endoscope according to the invention, color image can be obtained by using can be obtained from two mapping areas, one being the area of the green, the other being the Area of white or magenta licit is.

Since cyan and yellow color filter elements are arranged alternately so that they can be matched with the respective picture elements, constituting the solid-state image pickup device, when these picture elements match the green Light (during the imaging area with green light) are exposed, one of the green components of the Object corresponding image signal recorded by all image elements. Are these picture elements dem white or magenta light (throughout the imaging area with white or magenta light), then image signals that include the red and blue components are also exposed each correspond, recorded at the same time through the cyan and yellow color filters. That has to

Result that signals of three different color components (red, green and blue) of the object through two Mapping areas are obtained. The time required for this is only two thirds of the time required for the device according to US-PS 40 74 306 is necessary to obtain the same result, and alignment errors are decreased.

In another prior art solid-state image pickup device (US Pat. No. 4,246,601) in addition to the cyan and yellow filters, white and green filters are arranged. For this reason, the efficiency to obtain red and blue component signals, less than with a device according to the invention. In addition, it is much more difficult to find a solid-state image pickup device of four different types of filters as such according to the invention, in which there are only two types of filters are. In this respect, the device is according to the invention

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The subject matter of the invention is explained with reference to the drawings

F i g. 1 shows a schematic representation of an endoscope designed according to the invention in a first one Embodiment;

F i g. 2 is a plan view of the endoscope of FIG. 1 mosaic filter used;

Fig. 3 is a Dia ^ amm of the spectral transmittance (Permeability) in the mosaic filter of FIG. 2 included cyan and yellow filters as well as the intensity the green light component picked up by the cyan and yellow filters;

4 shows a schematic representation of an endoscope designed according to the invention in a second Execution forro;

F i g. 5 is a diagram of the spectral distribution (energy distribution) of the green and stomach light containing Light source and the spectral transmittance of the in the mosaic filter from FIG. 2 contained cyan and yellow filter;

F i g. 6 is a diagram showing the distribution of the air generated by a combination of the light source filters of FIG. 3 included Color component light;

F i g. 7 is a diagram of the spectral transmittance of the endoscope of FIG. 4 used Infrared absorption filter;

F i g. FIG. 8 is a diagram showing the distribution of the air generated by a combination of the light source filters of FIG. 5 and des Infrared absorption filter which corresponds to the one shown in FIG. 7 shown spectral transmittance has obtained color component light.

The in Fig. 1 in its structure shown schematically endoscope according to the invention comprises an endoscope body 1, a light source unit 2, a synchronization circuit 3, an image signal processing circuit 4 and an image viewer 5, e.g. B. a cathode ray tube.

In an end part of the endoscope body 1 to be inserted into a body to be observed, at least an imaging optical system (imaging lens) 12 for forming an image of an object inside the body, a self-scanning solid-state image recording device 13. z. B. a cold cathode discharge tube (CCD), and one end 15 of a light guide 14, which serves the object; to illuminate contain. On the solid-state imaging device 13

For example , cyan and yellow filters (CY and V color filters) are provided in a mosaic arrangement as shown in FIG. The end part of the in Fi g. The endoscope body 1 shown in FIG. 1 also has a glass window 11 through which the imaging lens 12 forms the image of the object on the image recording surface of the solid-state image recording device 13. The end 15 of the light guide 14 emits light onto the object through the glass window 11. An electrical image signal detected by the solid-state image recording device 13 is supplied to the image signal processing circuit 4 through a conductor bundle 17 and displayed as an image on the image display device 5. The conductor bundle 17 contains conductors for supplying clock signals which are used to drive the solid-state image pickup device 13, and the image signal processing circuit 4 contains a circuit in order to generate the clock signals for driving the CCD

The light source unit 2, which forms part of the endoscope, is equipped with flash lamps 25, 26 which can be turned on and off alternately at high speed. A color temperature compensation filter is attached to the flash lamp 25 24. A green feed 23 is arranged on the flash lamp 26. The green and white Light emitted by these light sources is passed through a semi-transparent mirror 22 as well as through an Inf.Äfotabsorptionsfilter 27 sent and sent to the End face 16 of the light guide 14 concentrated by a condenser lens 21. The flash lamps 25,26 are from a (not shown) energy source and in synchronized relation to respective partial images switched on and off by the synchronization circuit 3.

As said above, those shown in FIG. Cyan and yellow color filters (CY and K filters) shown in Fig. 2 are arranged on respective picture elements of the solid-state image pickup device 13 (Fig. 1). Therefore, if an odd image field (1, 3, 5, ... field) corresponds to the green one shown in FIG. 3 and is exposed to light generated by the flash lamp 26 and the green filter 23, the green component signal (G) of the object is recorded both from picture elements on which cyan filters are arranged and from picture elements on which yellow filters are arranged, as shown in FIG .3 shows. As a result, the green component signal of the subject is picked up by all the picture elements of the solid-state image pickup device 13. Then, when a straight image field (2nd, 4, 6, ... field) is the white (blue + green + red) light (W), which has the characteristics shown in Fig. 3 and through the flash lamp 25 as well as the color temperature - Compensation filter 24 is generated, is exposed to the cyan component signal (CY) of the object from the

Image elements recorded on which the in F i g. 2 are arranged, and the yellow component signal (Y) of the object is picked up by the picture elements on which the yellow filters are arranged, as shown in FIG. That is, Fig. 3 shows that the cyan and yellow component signals of the object are obtained from the even field. Then the green, cyan and yellow component signals are stored in a memory (buffer memory) included in the image signal processing circuit. saved A blue component signa! is generated by subtracting the green component signal from the cyan component signal, a red component signal is generated by subtracting the green component signal from the yellow component signal.

lcnsignal generated. In this way, television image signals are produced by the signal processing circuit 4. In this case is the resolving power for the blue and red component signals of the object half the resolution for the green component signal. Because the resolving power for the television pictures is determined by the resolution for the green component signal, However, the signal recording method explained does not adversely affect the color image resolution. In addition, because the signals of all color components of the object are obtained from two fields is the time to obtain all of the color component signals, two-thirds that of the one described above conventional system for sequentially picking up the three primary color image signals is required. Accordingly, the endoscope shown in Fig. 1 eliminates the problem associated with the temporal Dimensioning of the recording of the three-primary color images is related and differs from that described above third, conventional system.

In the embodiment explained above, the synchronized relation to the partial images are and turned off flash lamps are used as the light sources. However, it is also possible to use light sources use where green and magenta filters are synchronized Relationship to the partial images are rotated. Furthermore, the cyan and yellow filters described in are arranged in a clear relationship to the respective picture elements of the solid-state image recording device, comprehensive mosaic filter by a vertical stripe in FIG. 2 strip filter provided must be replaced.

The F i g. FIG. 4 shows another embodiment for an endoscope according to the invention, FIG. 1 same Elements are denoted by the same reference numerals. The in Fig. 4 has the same endoscope Structure like that in FIG. i shown with the exception that instead of the color temperature compensation filler 24 a magenta filter 24 'is arranged on the flash lamp 25 and that instead of the semi-transparent mirror 22 a dichroic mirror 22 ', which can reflect green light and transmit gastric light, for Application comes.

The cyan and yellow color filters (CY and / filters) shown in FIG. 2 are arranged on the respective picture elements of the solid-state image pickup device 13 in the case of FIG. Therefore, for example, if an odd image field (1, 3, 5, ... field) turns green light that corresponds to the one shown in FIG. 5 has the characteristic values shown and is generated by the flash lamp 26 and the green filter 23, the green component signal (C) of the object, as in FIG. 6, recorded both of picture elements on which cyan filters are arranged and of picture elements on which yellow filters are arranged, as shown in FIG. Then, when an even field of view is a magenta light (M) which has the characteristics shown in FIG. 5 has characteristic values and is generated by the flash lamp 25 and the magenta filter 24 ', the blue component signal (B) of the object from the picture elements at which the in FIG. 2 are arranged, and the red component signal (R) of the object is picked up by the picture elements on which the yellow filters are arranged, as shown in FIG. That is, FIG. 6 shows that the blue and red component signals of the object are obtained from the even field. In this case, the resolution for the blue and the red component signal is half of the resolution for the green component signal. However, the signal recording method carried out in the endoscope of FIG. 4 does not adversely affect the resolution for the color television pictures, as was already the case with FIG. 1 was explained. Furthermore, in the endoscope of FIG. 4 does not address the problem associated with recording three-primary color images because signals of all color components of the object are obtained from two fields, and the time required to obtain all color component signals is two-thirds that of the third described above conventional system is required.

As shown in FIG. 4, the infrared absorption filter 27 is arranged in the light source unit 2, and this filter can be the one shown in FIG. 7 characteristic values of the spectral Have transmittance. In this case, the in F i g. 8 spectral characteristics shown by the combination the light source filter 23 and 24 'with the characteristic values shown in FIG. 5 and the infrared absorption filler 27 having the characteristics shown in FIG. 7 can be obtained. As a result, with the endoscope of Fig. 4 to achieve excellent color rendering.

Furthermore, the image signal processing circuit 4 can process the image signals in various ways. For example the green image signals obtained in the odd fields and those from the even-numbered fields can be used Fields received blue and red image signals alternately for the respective fields on a color television monitor being represented. Alternatively, these image signals can first be stored in a memory and retrieved to the respective fields of the color television monitor to view the image signals as simultaneous To process color image signals.

For this purpose 3 sheets of drawings

Claims (12)

Patent claims: 1. Endoscope for observing and recording the inside of a body cavity or machine with an optical imaging system that generates an image of an object, with a self-scanning solid-state image recording device that converts the image generated by the optical imaging system into an electrical signal and with a lighting device illuminating the object, wherein the optical imaging system, the solid-state image recording device and the lighting device are arranged on an endoscope body which can be inserted into a body cavity or the interior of a machine, characterized in that the solid-state image recording device (13) only uses cyan and yellow color filters (CY , Y) is provided. which are arranged alternately in correspondence with respective oil elements forming the solid-state image pickup device (13), and that, when green light is emitted from the lighting device onto the object, all picture elements of the solid-state image pickup device receive an image signal corresponding to the green component of the object, and when white light is emitted from the lighting device to the object, the picture elements of the solid-state image pickup device on which the cyan color filters are arranged, an image signal corresponding to the cyan component of the C ^ object and the picture elements of the solid-state image pickup device to which the yellow-colored filters are arranged, recorded an image signal corresponding to the yellow components of the object, and electrical processing is then carried out to generate a color image of these image signals. 2. Endoscope according to claim 1, characterized in that the solid-state image recording device (13) by a conductor bundle (17) with an image signal processing circuit (4) is connected. 3. Endoscope according to claim 2, characterized in that that the image signal processing circuit (4) is connected to an image display device. 4. Endoscope according to claim 1, characterized in that the lighting device (14, 15) is connected to a light source unit (2). essentially two flashlights (25,26). an on the color temperature compensation filter (24) arranged on one flash lamp, one on the other flash lamp arranged green filter (23) and a semi-transparent mirror (22), the light from both Color temperature compensation filter as well as from the green filter to one end (16) of the lighting device directs, includes. 5. Endoscope according to claim 4, characterized in that that the light source unit (2) is in the light path downstream of the semi-transparent mirror (22) arranged infrared absorption filter (27) comprises. 6. Endoscope according to claim 4, characterized in that the flash lamps (25, 26) to a synchronization circuit (3) connected to the rags in synchronized relation to the turns the respective partial images on and off alternately. 7. Endoscope for observing and recording the inside of a body cavity or a device with an optical imaging system that generates an image of an object, with a self-scanning solid-state image recording device that converts the image produced by the imaging system into an electrical signal and with a lighting device illuminating the object, wherein the optical image generation system, the solid-state image recording device and the lighting device are arranged on an endoscope body which can be inserted into a body cavity or the interior of a machine, characterized in that the solid-state image recording device (13) only has cyan and yellow color filters (CY, Y) which are alternately arranged in correspondence with respective picture elements constituting the solid-state image pickup device (13), and that when green light is emitted from the lighting device on the object, all the mess of the solid-state image pickup device an image signal corresponding to the green component of the object, and when magenta is emitted from the lighting device onto the object, the elements of the solid-state image pickup device on which the cyan color filters are arranged, an image signal corresponding to the blue component of the object and the picture elements of the solid-state picture-taking device, on which the yellow color filters are arranged, record an image signal corresponding to the red component of the object, and these image signals are then electrically processed to generate a color image. 8. Endoscope according to claim 7, characterized in that that the solid-state image recording device (13) through a conductor bundle (17) with an image signal processing circuit (4) is connected. 9. Endoscope according to claim 8, characterized in that the image signal processing circuit (4) with a vision device (1). 10. Endoscope according to claim 7, characterized in that that the lighting device (14, 15) is connected to a light source unit (2), essentially two flash lamps (25, 26), a magenta filter arranged on one flash lamp (24 '). a green filter (23) arranged on the other flash lamp and a dichroic mirror (22 '). the light from both the magenta filter and the green feed to one end (16) of the lighting device directs, includes. 11. Endoscope according to claim I 10. characterized in that that the light source unit (2) is in the light path downstream of the dichroic mirror (22 ') arranged infrared absorption filter (27) comprises 12. Endoscope according to claim 10, characterized in that that the flash lamps (25, 26) to a synchronization circuit (3) connected, the lamps in a synchronized relationship / u the turns the respective partial images on and off alternately.